The following representative abbreviations may be used herein:
SDS-PAGE: Sodium dodecylsulfate polyacrylamide gel electrophoresis.
HEPES: 4-(2-hydroxyethyl)-1-piperazine ethanesulfonic acid.
Poly(rI). poly(rC)-agarose: poly(inosinate). poly(cytidylate) double stranded polynucleotide covalently bound to agarose through poly(rI).
2-5A, 2',5'-oligoadenylate or p.sub.3 A.sub.n : Oligomer of adenylic acid with 2',5'-phosphodiester linkages and a 5' terminal triphosphate group.
AMP: 5'-adenylic acid or adenosine 5'-monophosphate.
ADP: Adenosine 5'-diphosphate.
ATP: Adenosine 5'-triphosphate. A.sub.2, A.sub.3 and A.sub.4 : Dimer, trimer and tetramer of AMP with 2',5'-phosphodiester linkages and without 5'-, 3'- or 2'-terminal phosphate groups.
pA.sub.3, ppA.sub.3 (or p.sub.2 A.sub.3), pppA.sub.3 (or p.sub.3 A.sub.3) 5'-terminal mono-, di- and triphosphates of A.sub.3.
2-azido-ATP or 2-N.sub.3 ATP: 2-azidoadenosine 5'-triphosphate.
2-Azido-ADP or 2-N.sub.3 ADP: 2-azidoadenosine 5'-diphosphate.
2-Azido-AMP or 2-N.sub.3 AMP: 2-azidoadenosine 5'-monophosphate.
8-Azido-ATP or 8-N.sub.3 ATP: 8-azidoadenosine 5'-triphosphate.
8-Azido-ADP or 8-N.sub.3 ADP: 8-azidoadenosine 5'-diphosphate.
8-Azido-AMP or 8-N.sub.3 AMP: 8-azidoadenosine 5'-monophosphate.
2,8-diazido-ATP or 2,8-N3ATP: 2,8-diazidoadenosine 5'-triphosphate.
2,8-diazido-ADP or 2,8-N.sub.3 ADP: 2,8-diazidoadenosine 5'-diphosphate.
2,8-diazido-AMP or 2,8-N.sub.3 AMP: 2,8-diazidoadenosine 5'-monophosphate.
x-N.sub.3 ATP: The group of azidonucleotides consisting of 2-azido-ATP, 8-azido-ATP and 2,8-diazido-ATP.
x-N.sub.3 ADP: The group of azidonucleotides consisting of 2-N3ADP, 8-N3ADP and 2,8-N3ADP.
x-N3AMP: The group of azidonucleotides consisting of 2-N3AMP, 8-N3AMP and 2,8-N3AMP.
2-azido-p3A3 or p3(A2-azido)3 5'-O-triphosphoryl-(2-azidoadenylyl(2,-5,)2-azidoadenylyl(2,-5,)2-azidoade nosine.
8-azido-p3A3 or p3(A8-azido)3 5'-O-triphosphoryl-(8-azidoadenylyl(2'-5')8-azidoadenylyl(2'-5')8-azidoade nosine.
The symbols A.sub.2 -azido, A.sub.8 -azido, A.sub.2,8 -diazido and A, as used in representing the oligomers described herein, shall mean, respectively, 2-azidoadenylyl, 8-azidoadenylyl, 2,8-diazidoadenylyl and adenylyl moieties linked to each other by 2',5'-phosphodiester linkages, but without phosphate groups on the 2'-terminal moiety of the oligomer. For example, the compound 2-azidoadenylyl(2'-5')adenylyl(2'-5')8-azidoadenosine may be represented as A.sub.2 -azido AA.sub.8 -azido The 5'-triphosphate thereof, namely 5'-0-triphosphoryl-(2-azidoadenylyl)(2'-5')adenylyl(2'-5')8-azidoadenosine , may be represented as pppA.sub.2-azido AA.sub.8 -azido or p.sub.3 A.sub.2-azido AA.sub.8-azido.
The symbol A.sub.x-azido as used in representing the oligomers described herein shall mean the group consisting of 2-azidoadenylyl, 8-azidoadenylyl and 2,8-diazidoadenylyl, as each is defined above.
The 2-5A system is widely accepted to be part of the antiviral mechanism of interferon and may also play a role in the regulation of cell growth. 2-5A synthesized from ATP by 2',5'-oligoadenylate synthetase [ATP: (2'-5')oligo(A)-adenylyltransferase (EC 2.7.7.19)]exerts its biological effects by binding to and activating its only known target enzyme, the unique 2-5A-dependent endoribonuclease, RNase L (EC 3.1.27). RNase L cleaves viral and cellular mRNA or rRNA, thereby inhibiting protein synthesis. Hovanessian et al, Eur. J. Biochem. 93:515-526 (1979); Kerr et al, Proc. Natl. Acad. Sci. USA. 75:256-260 (1978). It has been reported that 2-5A protects plant tissue from infection by tobacco mosaic virus. Devash et al, Science 216:415-416 (1982). It has also been reported that 2-5A inhibits avian myeloblastosis virus, Rous associated virus 2, and Moloney murine leukemia virus. Liu et al., Biochem. Biophys. Res. Commun. 145:291-297 (1987).
RNase L may not be the only target whose activity is modulated by 2-5A. The latter has also been implicated to be involved in the regulation of lymphocyte mitogenesis or cap methylation of viral mRNA through mechanisms different from RNase L activation.
Molecules containing azido groups form covalent bonds to proteins through reactive nitrene intermediates, generated by low intensity ultraviolet light. Knowles, Acct. Chem Res. 5:155-160 (1972); Hoyer et al., Ann. N.Y. Acad. Sci. 346:380-381 (1980). In particular 2- and 8-azido analogues of purine nucleotides have been used as site-directed photoprobes to identify nucleotide binding proteins in crude cell extracts. Evans et al., J. Biol. Chem. 260:7800-7804 (1985); Malkinson et al., Cancer Res. 46:4626-4630 (1986). 2- and 8-azido nucleotides have also been used to map nucleotide binding domains of purified proteins. Hegyi et al., Biochemistry 25:5793-5798 (1986); Garin et al., Biochemistry 25:4431-4437 (1986); Lunardi et al., J. Biol. Chem. 262:15172-15181 (1987). They have also been used to study enzyme kinetics of purified proteins. Boulay et al., Biochemistry 24:7372-7379 (1985). However, (2'-5')oligomers of 2- and 8-azido nucleotides have not been hitherto known.